C88.90 ICD-10-CM Code: Malignant immunoproliferative disease, unspecified not having achieved remission
C88.90 maps to CMS-HCC V28 21. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools
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FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)
C88.90
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceMalignant immunoproliferative disease, unspecified not having achieved remission
A cancer of immune cells of an unspecified type that has not responded to treatment or is still active.
Buddy Insight
Malignant immunoproliferative disease, unspecified, not having achieved remission is the least specific code in the immunoproliferative disease category, used when neither the type of immunoproliferative disease nor the site can be determined from available documentation.
CMS-HCC V28
MappedHCC 21
Coefficient HCC 21: 0.671 (Community Non-Dual Aged (CNA))
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 010
Code-level coefficient reference
ESRD/PACE
MappedHCC 10
Code-level coefficient reference
RXHCC
MappedHCC 21
Code-level coefficient reference
Code Book Path
Inclusion Terms
Official- Immunoproliferative disease NOSInherited from C88.9
- Immunoproliferative disease NOS not having achieved remission
- Immunoproliferative disease NOS with failed remission
- Malignant immunoproliferative disease, unspecified NOS
- Malignant immunoproliferative disease, unspecified with failed remission
Excludes 2
Official- Kaposi's sarcoma of lymph nodes (C46.3)Inherited from C81-C96
- secondary and unspecified neoplasm of lymph nodes (C77.-)Inherited from C81-C96
- secondary neoplasm of bone marrow (C79.52)Inherited from C81-C96
- secondary neoplasm of spleen (C78.89)Inherited from C81-C96
Related Codes
Includes
OfficialNo Includes notes are included in this display for C88.90. Check the code and parent instructions in the Code Book.
Excludes 1
Official- B-cell lymphoma, unspecified (C85.1-)Inherited from C88
- personal history of other malignant neoplasms of lymphoid, hematopoietic and related tissues (Z85.79)Inherited from C88
Code First
OfficialNo Code First sequencing instructions are included in this display for C88.90. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for C88.90. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for C88.90. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is C88.90 an HCC code?
Yes. C88.90 (Malignant immunoproliferative disease, unspecified not having achieved remission) maps to HCC 21, Lymphoma and Other Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.671. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.
Coder answer: C88.90 is billable and maps to V28 HCC 21, Lymphoma and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- C88.90
- Description
- Malignant immunoproliferative disease, unspecified not having achieved remission
- HCC (V28)
- HCC 21 — Lymphoma and Other Cancers
- RAF reference coefficient
- 0.671
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work C88.90 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for C88.90
For C88.90, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Coder workflow notes
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What This Code Means
C88.90 is the ICD-10-CM diagnosis code for malignant immunoproliferative disease, unspecified not having achieved remission. A cancer of immune cells of an unspecified type that has not responded to treatment or is still active. C88.90 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of lymphoid, hematopoietic and related tissue (c81-c96).
Under the CMS-HCC V28 risk adjustment model, C88.90 maps to Lymphoma and Other Cancers (HCC 21) with a source-labeled community, non-dual, aged reference coefficient of 0.671. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.
Use this code only when the specific type of immunoproliferative disease cannot be determined from documentation. For C88.90, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for C88.90 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when the specific type of immunoproliferative disease cannot be determined from documentation
- •The fifth character '0' indicates the disease has not achieved remission; document treatment response status
Clinical Significance
Malignant immunoproliferative disease, unspecified, not having achieved remission is the least specific code in the immunoproliferative disease category, used when neither the type of immunoproliferative disease nor the site can be determined from available documentation. This code should prompt a query to the provider for additional diagnostic information. Active disease that has not achieved remission indicates ongoing malignant process.
Documentation Requirements
- ✓Even for unspecified codes, documentation should include available clinical findings, laboratory results, and any pathology that has been obtained.
- ✓The reason the specific type cannot be determined should be evident in the record.
- ✓Treatment plan, response assessment, and active disease status must be documented.
- ✓Provider queries for additional specificity should be documented.
Commonly Confused Codes
- •C88.91 (malignant immunoproliferative disease, unspecified, in remission) requires documented remission.
- •C88.80 (other malignant immunoproliferative diseases) is used when the type is identified but does not fit specific subcategories.
- •C88.00-C88.41 provide more specific codes that should be used whenever possible.